The common rivet has a head and a shank. The shank is inserted through aligned holes from one side of assembled metal sheets or plates or other parts. The rivet head engages one side of the assembly and the shank extends through the other side. The extended end of the shank is struck and upset or otherwise deformed to form a second head engaging the other side of the assembly and thus secure the parts at the rivet site. In a blind rivet situation only one side of the assembly is available for the riveting operation. The shank can be inserted through the assembly so that the rivet head engages the accessible side, but the blind side is not accessible for upsetting the protruding shank from that side to form the opposing rivet head.
Blind rivets often have a hollow shank like a tube or sleeve with the rivet head at one end. A mandrel with a mandrel head is inserted through the open end of the tube. The head of the mandrel is about the same diameter as the tubular body and the bottom of the mandrel head lies against the open end of the tube. The shaft extends axially the length of the tube and through a suitable hole in the rivet head. The rivet body and mandrel head are inserted through the holes in the assembled parts so that the rivet head engages the accessible side of the assembly. The blind end of the tubular body and the mandrel head extend through the assembly with just enough material protruding from the blind side for formation of a rivet head on that side. A tool is used to pull on the end of the mandrel extending through the rivet head. The mandrel is pulled so that the mandrel head compresses and deforms or upsets the end of the rivet body to form a second rivet head against the blind side of the assembly.
Sometimes blind rivets include a latent adhesive deposited within the region bounded by the rivet body and the mandrel shank. One or more radial holes of suitable size and location are formed in the tubular body. When the end of the tube is upset, a small amount of adhesive is extruded through the holes in the sleeve into contact with the surfaces of the insertion holes of the parts to be joined. The adhesive may also penetrate between the faying surfaces of the parts. The adhesive dries or cures to supplement the mechanical holding strength of the blind rivet. The design of such blind rivets has required a compromise in the length and properties of the sleeve so that the blind-side rivet could be easily formed using the mandrel head upsetting tool. The short stroke of the head forming operation limited the amount of rivet head that could be formed and the amount of adhesive that could be effectively extruded into the rivet region.
It is an object of the present invention to provide an adhesive filled blind rivet that comprises a tubular rivet body that is capable of storing and delivering larger volumes of adhesive while being folded into a blind side rivet head. It is a further object of the present invention to provide a method of installing the adhesive filled blind rivet to form a stronger bond between the assembled parts such that these parts are suitable for a structural assembly.